The present invention relates to a photoelectric cell including an optoelectronic receptor circuit provided with a photoreceptor component, the photoreceptor surface of which is able to receive a spot of light, and comprises a first photoreceptor area and a second photoreceptor area, wherein both areas are juxtaposed.
As it is known, a photoelectric cell of the xe2x80x9creflexxe2x80x9d type emits a light beam towards a reflector and detects an object by interruption of the reflected light beam. A photoelectric cell of the xe2x80x9cproximityxe2x80x9d type emits a light beam towards the object to be detected and for triangulation purposes makes use of the light beam reflected by the object in order to determine whether the distance is smaller or larger than a distance called the detection range. A photoelectric cell which may operate in reflex mode or in proximity mode, is described in document EP 923 140. The receiving portion of this cell has several optically sensitive areas connected to a processing circuit via switches which enable the operating mode of the cell to be selected. The considered areas are photodiode areas, certain of which may be enabled by means of the switches.
Sometimes there is the risk, notably with poorly reflecting targets located at a relatively large distance, that the signal to noise ratio of the cell may be too low.
The object of the invention is to improve for certain applications, the photoreceptor portion of a cell which may be used both in reflex mode and proximity mode.
According to the invention,
the photoreceptor surface of the component has two juxtaposed photoreceptor areas, wherein these areas differ by their microelectronic nature,
the cell has means for assigning the photoreceptor circuit to a reflex operating mode or to a proximity operating mode,
the first photoreceptor area is provided with a first output enabled in the reflex operating mode,
the second area is with analog detection of the position of the spot of light and is provided with a second output enabled in the proximity operating mode.
The area for analog detection of position has a third output which is enabled in the proximity operating mode and which may either be distinct from the first output, or may coincide with the first output. The first area is preferably a photodiode area.
The second output then forms the close channel, and the third output forms the remote channel, respectively, of the analog area for the detection of position, wherein the first and second outputs may be switched one exclusively from the other, to a processing circuit by means of an operating mode selection switch, which forms the mode assigning means. The component is then a component with three outputs and has a cathode common to the two areas.